Yao Shi

Renji Hospital, Shanghai, Shanghai Shi, China

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Publications (12)16.83 Total impact

  • Journal of Digestive Diseases 06/2007; 8(2):107-19. · 1.85 Impact Factor
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    ABSTRACT: Epidemiological and experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) are chemopreventive agents of gastrointestinal cancers, but few studies on gastric cancer have been carried out. A decrease in folic acid supplement and subsequent DNA hypomethylation are related to gastrointestinal cancers, and it has been shown that high-dose folic acid may interfere with gastric carcinogenesis in dogs. The objective of this study was to investigate the effects of rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, and folic acid on the chemoprevention of gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Wistar rats, and to evaluate the cell proliferation of gastric mucosa in different experimental groups. Eighty male Wistar rats were randomly divided into five groups (16 rats in each group). In the control group, the rats were given pure water and basal diet. In the MNNG group, the rats received MNNG in drinking water (100 mg/L) and basal diet. In the MNNG + low-dose rofecoxib group, the rats were given MNNG and rofecoxib 5 mg/kg per day with basal diet. In the MNNG + high-dose rofecoxib group, the rats were given MNNG and rofecoxib 15 mg/kg per day with basal diet. In the MNNG + folic acid group, the rats were given MNNG and folic acid 5 mg/kg per day with basal diet. The experiment was terminated at 50 weeks, and all rats were killed. Blood samples of 3 mL were obtained for measurement of serum folic acid concentrations in the control group, the MNNG group and the MNNG + folic acid group by using chemiluminescent method. The stomach was removed from all rats for histopathological examination and immunohistochemical study. Proliferating cell nuclear antigen (PCNA) expression in gastric epithelial cells was also determined. In the MNNG group, five of 11 rats (45.5%) developed gastric cancer, while in all other four groups no gastric cancer was found (P < 0.05). The positivity rate of PCNA expression in the cancerous tissues was significantly higher than that in the non-cancerous tissues (80.0%vs 14.1%, P < 0.05). The positivity rate of PCNA expression in the gastric mucosal cells of the MNNG group was significantly higher than that in the other four groups. The mean serum folic acid concentration of rats was significantly higher in the MNNG + folic acid group (193.70 +/- 60.73 ng/mL) than those in the control group (84.21 +/- 25.26 ng/mL) and the MNNG group (72.27 +/- 16.70 ng/mL, P < 0.05). It was shown that both low- and high-dose rofecoxib as well as folic acid interfered with the development of gastric cancer induced by MNNG in Wistar rats. The results indicate that rofecoxib as well as folic acid interferes with gastric carcinogenesis induced by MNNG in Wistar rats, and the suppression of gastric cell proliferation may play a crucial role in the chemoprevention of gastric cancer by rofecoxib and folic acid. The higher serum folic acid concentration of rats may play an important role in the prevention of gastric cancer.
    Chinese Journal of Digestive Diseases 02/2006; 7(3):134-40.
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    ABSTRACT: To investigate the effects of Helicobacter pylori (Hp) infection on neural expression in stomach and spinal cord, and to investigate the mechanism of functional dyspepsia after Hp infection. Thirty-five female C57BL/6 mice were randomly divided into three groups: Group A (acute infection group, undergoing intragastric gavage of Hp suspension every other day for 3 times and then observed for 2 weeks, 15 mice), Group B (chronic infection group, undergoing intragastric gavage of Hp suspension every other day for 3 times and then observed for 2 weeks, 15 mice) and control group (undergoing intragastric gavage of normal saline every other day for 3 times and then observed for 2 weeks, 5 mice). After the observation the mice were killed and their stomachs were taken out to undergo gastric histology and bacterial colonization by HE staining and Warthin-Starry staining respectively. Their spinal cords of thoracic and lumbar segments were taken out too. Immunohistochemistry was used to detect the expression of Fos, vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP) in the stomach and spinal cord. Three mice died 12 weeks after Hp infection. The rate of Hp colonization, mainly localized in pyloric gland region, was greater in Group B than in Group A, and was 0 in the control group. The severity of inflammation as shown by mononuclear cell infiltration, and activity of inflammation as shown by polymorphonuclear cell infiltration, in the pyloric gland region, proventriculus-glandular stomach region, and corpus gland region were more pronounced in Groups A and B, especially in Group B, than in the control group. The expression values of Fos, VIP, and CGRP in the stomach of Group A were 3.1 +/- 1.4, 4.5 +/- 1.8, and 2.4 +/- 0.8 respectively, all not significantly different from those of Group B (3.1 +/- 1.3, 3.5 +/- 1.6, and 2.2 +/- 0.8, all P > 0.05). The expression values of Fos, VIP, and CGRP in the spinal cord of Group A were 3.8 +/- 1.2, 3.2 +/- 1.5, and 2.2 +/- 0.6, all not significantly different from those of Group B (3.4 +/- 0.7, 2.6 +/- 1.2, and 2.5 +/- 1.1, all P > 0.05 for all). However, the neural expression values in both acute and chronic infection groups were significantly higher than those in the control group (2.4 +/- 0.9, 1.6 +/- 0.9, and 1.2 +/- 0.8 in stomach; and 2.0 +/- 1.6, 1.2 +/- 1.1, and 1.2 +/- 1.1 in spinal cord, P < 0.05 for all). Hp infection, both acute and chronic, induces gastric histological changes such as inflammation and activity, and enhances the Fos, VIP, and CGRP expression in stomach and spinal cord, which can be a basis for symptom generation in dyspeptic patients with Hp infection.
    Zhonghua yi xue za zhi 01/2006; 86(4):255-9.
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    ABSTRACT: The safety of Helicobacter pylori "test-and-treat" and "test-and-endoscopy" strategies for the management of young patients with uninvestigated dyspepsia has not been evaluated in Shanghai. A total of 14,101 consecutive patients with dyspepsia receiving endoscopy in our hospital from October 2002 to December 2003 were retrospectively studied. The detection rates of esophageal or gastroduodenal malignancies and alarm symptoms were investigated, and H. pylori status was assessed. A total of 202 (1.4%) gastrointestinal (GI) malignancies were found, including 162 cases (1.15%) of gastric cancer, 4 of gastric lymphoma, 35 (0.25%) of esophageal cancer and 1 case of duodenal cancer. Among those patients with GI malignancies, 99 (49.0%) were infected with H. pylori and 108 (53.5%) presented with alarm symptoms. Eighteen patients (0.46%, 18/3952) under 45 years of age were diagnosed as having gastric cancer. Of these patients, 5 (27.8%) presented with alarm symptoms and 13 (72.2%) were infected with H. pylori. If the H. pylori "test-and-treat" strategy were used in dyspeptic patients under the age of 45 years without alarm symptoms in the Shanghai region, then 13 cases (72.2%) of gastric cancer would be missed. If the H. pylori "test-and-endoscopy" strategy were applied, then 3 cases (16.7%) of gastric cancer would be missed. H. pylori "test-and-treat" and "test-and-endoscopy" strategies are both not suitable for the management of patients with uninvestigated dyspepsia in Shanghai. For most Shanghai dyspeptic patients, prompt endoscopy should be recommended as the first-line initial management option.
    Scandinavian Journal of Gastroenterology 10/2005; 40(9):1028-31. · 2.33 Impact Factor
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    ABSTRACT: To investigate the anti-inflammatory mechanism of oxymatrine in dextran sulfate sodium (DSS)-induced colitis of rats. Acute colitis was induced by giving 2% DSS orally in drinking water for 8 d. Twenty-six male rats were randomized into oxymatrine-treated group (group A, 10 rats), DSS control (group B, 10 rats) and normal control (group C, 6 rats). The rats in group A were injected muscularly with oxymatrine at the dosage of 63 mg/(kg.d) from d 1 to 11 and drank 2% DSS solution from d 4 to 11. The rats in group B were treated with 0.9% saline in an equal volume as group A and drank 2% DSS solution from d 4 to 11. The rats in group C were treated with 0.9% saline as group B from d 1 to 11 and drank water normally. Diarrhea and bloody stool as well as colonic histology were observed. The levels of serum tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were determined by ELISA, and nuclear factor-kappaB (NF-kappaB) activity and the expression of inter-cellular adhesion molecule-1 (ICAM-1) in colonic mucosa were detected by immunohistochemistry method. Compared with DSS control group, the inflammatory symptoms and histological damages of colonic mucosa in oxymatrine-treated group were significantly improved, the serum levels of TNF-alpha, IL-6, and the expression of NF-kappaB, ICAM-1 in colonic mucosa were significantly reduced. The fact that oxymatrine can reduce the serum levels of TNF-alpha, IL-6, and the expression of NF-kappaB and ICAM-1 in colonic mucosa in DSS-induced colitis of rats indicates that oxymatrine may ameliorate the colonic inflammation and thus alleviate diarrhea and bloody stool.
    World Journal of Gastroenterology 09/2005; 11(31):4912-5. · 2.55 Impact Factor
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    ABSTRACT: To verify the safety of Helicobacter pylori (Hp) 'test-and-treat' and 'test-and-endoscopy' strategies for management of uninvestigated dyspepsia in Shanghai patients. 14,101 consecutive patients presented with dyspepsia receiving endoscopy during Oct. 2002 to Dec. 2003 were retrospectively analyzed in this study. The detective rate of esophageal or gastroduodenal malignancies and alarm symptoms were investigated and Hp status was assessed. Total 202 (1.43%) malignancies were found, including gastric cancer in 162 (1.15%), malignant gastric lymphoma in 4, esophageal cancer in 35 (0.25%) and duodenal cancer in 1. Among those patients with malignancies, ninety-nine (49.0%) patients were infected with Hp and 108 (53.5%) presented with alarm symptoms. Eighteen patients (0.46%) under the age of 45 years were diagnosed as gastric cancer. Among these patients, 5 (27.8%) presented with alarm symptoms and 13 (72.2%) were infected with Hp. If the Hp 'test-and-treat'strategy was used in dyspeptic patients under the age of 45 years without alarm symptoms in Shanghai region, then 13 cases (72.2%) of gastric cancer would be missed. If the Hp 'test-and-endoscopy' strategy was applied, then 3 cases (16.7%) of gastric cancer would be missed. Hp 'test-and-treat' and 'test-and-endoscopy' strategies are all not suitable for the management of uninvestigated dyspepsia in Shanghai patients. For most Shanghai adult dyspeptic patients, prompt endoscopy should be recommended as the first-line initial management option.
    Zhonghua nei ke za zhi [Chinese journal of internal medicine] 04/2005; 44(3):195-7.
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    ABSTRACT: The experimental evidence that long-term colonization of Helicobacter pylori results in the development of gastric cancer in Mongolian gerbils has been reported only by two Japanese groups to date. This study aimed to investigate the carcinogenicity of H. pylori infection in a Mongolian gerbil model. Thirty-six Mongolian gerbils (inner Mongolian origin) were divided into two groups (male to female ratio, 1:1) and orally inoculated with a standard H. pylori strain (ATCC43504) or H. pylori161 (isolated from a Chinese patient with gastric adenocarcinoma), respectively, once a week for 5 weeks. Another 10 control gerbils were given phosphate-buffered saline. The animals were killed 8, 20, 28 and 84 weeks after inoculation for bacterial and histological examination. Seven inoculated gerbils died at the week 42. Overall, H. pylori colonization was detected in 24 (83%) of the 29 available inoculated gerbils. The gastric lesions were aggravated gradually over time. At week 84, moderate to severe gastritis, characterized by diffuse infiltration of mononuclear cells and formation of multiple lymphoid follicles in mucosa and submucosa, and even the lymphoepithelial lesions, were observed. Epithelial hyperplasia were dominant in almost all gerbils. Four (24%) of the 17 animals had hyperplastic polyps. Intestinal metaplasia were rarely seen (in three gerbils). Well-differentiated gastric adenocarcinomas developed in three (18%) of the 17 gerbils after 84 weeks. Of the three gerbils, one female gerbil was infected with H. pylori161 and the others (one male and one female) were infected with ATCC43504. The present study reconfirms that H. pylori infection alone can induce gastric adenocarcinoma in Mongolian gerbils and suggests that different species of gerbil and both standard and clinically isolated H. pylori strains can be used for investigating the carcinogenesis of H. pylori. This is the first report of the development of gastric cancer in female gerbils, which highlights the importance of using both sexes to investigate the pathogenesis of H. pylori and whether host susceptibility is influenced by sex.
    Journal of Gastroenterology and Hepatology 11/2004; 19(10):1192-8. · 3.33 Impact Factor
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    ABSTRACT: To evaluate the roles of folic acid and beta-carotene in the chemoprevention of gastric and other gastrointestinal (GI) cancers. In a randomized, double-blind, placebo-controlled trial, a total of 216 patients with atrophic gastritis were randomly assigned to one of the four groups: (1) folate (FA, 20 mg per day plus vitamin B(12) 1 mg, intramuscularly, per month for one year, then 20 mg two times a week plus 1 mg per three months for the next year); (2) natural beta-carotene (N-betaC, 30 mg per day for first year, then 30 mg two times a week for the next); (3) synthetic beta-carotene (S-betaC, administered as in N-betaC); and (4) placebo. Follow-ups continued from 1994 to 2001. A total of 7 new cases of gastrointestinal cancers were diagnosed with 3 stomach, 1 colon and 1 esophageal cancers occurring in the placebo group; 1 stomach cancer in both of the N-betaC and S-betaC groups, and no cancer occurring in FA group. In terms of GI cancers, there was a significant reduction in the FA group, compared with the placebo group (P = 0.04). A similar trend was observed in both N-betaC and S-betaC groups (P = 0.07 - 0.08). Taken together, the three intervention groups displayed a highly significant decrease in occurrence (P = 0.004, vs placebo), and a lower risk for GI cancers (OR = 0.12; 95% confidence interval, 0.03 - 0.51). For development of gastric cancer, any one of the three active-treated groups did not reach statistically significant reduction. The FA group showed obvious improvement of the gastric mucosal lesions with more patients displaying lesions reversed or stable atrophy and inflammation (P = 0.04), reversed intestinal metaplasia (P = 0.06) at the end of follow-up, and reversed displasia (P = 0.017) at 12 months. Two cases of false jaundice were found in beta-carotene groups with no influence on administration, and no side-effects were reported in FA group. This trial revealed the interventional effect of folic acid on the development of GI cancers, a similar effect of beta-carotene was also detected. Also, folic acid may be of use to treat atrophic gastritis by preventing or reversing the precancerous lesions.
    Chinese medical journal 02/2003; 116(1):15-9. · 0.90 Impact Factor
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    ABSTRACT: AIMS: To investigate the characteristics of gastric cancer in autofluorescence images.METHODS: A double-channel laser scanning confocal microscope with an argon ion laser (excitation wavelength 488 nm) and helium−neon laser (excitation wavelength 543 nm) were used to detect autofluorescence from 16 gastric cancer tissue specimens and corresponding normal gastric tissue.RESULTS: Autofluorescence from normal gastric tissue produced a green-colored image. The intensity of red color increased obviously in all gastric cancer tissues (100%) after illumination and the tissues produced a reddish-brown-colored image.CONCLUSIONS: A reddish-brown image is characteristic of autofluorescence in gastric cancer detected by an argon ion laser and helium−neon laser with a double-channel laser scanning confocal microscope. Autofluorescence imaging analysis is useful in the diagnosis of gastric cancer.
    Chinese Journal of Digestive Diseases 09/2002; 3(3):95 - 98.
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    ABSTRACT: OBJECTIVE: The cag pathogenicity island (cag PAI) has been reported to be the major factor controlling the virulence of Helicobacter pylori and has been associated with clinical outcome after H. pylori infection. The role of cag PAI genes in the pathogenicity of H. pylori infection remains to be established. The aim of the present study was to investigate: (i) the prevalence of cagA, cagE and cagT, the representative genes of cag PAI status, in H. pylori strains isolated from patients with various gastroduodenal diseases in the Shanghai region; and (ii) the relationship between the presence of these genes and different gastroduodenal diseases.METHODS: Ninety-nine H. pylori strains were isolated from patients with chronic superficial gastritis (17), chronic atrophic gastritis (21), gastric ulcers (19), duodenal ulcers (23) and gastric cancer (19). The prevalence of the cagA, cagE, and cagT genes was studied in these strains by using the polymerase chain reaction (PCR) method.RESULTS: The total prevalences of cagA, cagE and cagT genes were 84.8, 99 and 84.8%, respectively, in the 99 strains of H. pylori tested. There was no significant difference in the prevalence of cagA, cagE or cagT in H. pylori isolated from different gastroduodenal diseases (all P > 0.05). Of the 98 cagE-positive isolates, 14 (14.3%) were cagA negative. Only one of 99 isolates was negative for both cagE and cagA. Of the 84 cagT-positive strains, two were cagA negative.CONCLUSIONS: Most of the H. pylori isolates in the Shanghai region may have intact cag PAI. It was found that cagE, but not cagA, could be used as a marker for the presence of cag PAI. There is no correlation between the integrity of cag PAI and the clinical outcome after infection with H. pylori.
    Chinese Journal of Digestive Diseases 12/2001; 2(3):133 - 136.
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    ABSTRACT: AIM:To study the effect of Helicobacter pylori (H. pylori) infection on gastric epithelial proliferation in the progression from normal mucosa to gastric carcinoma.METHODS:Gastric biopsy specimens from normal controls (n = 11), superficial gastritis (n = 32), atrophic gastritis with intestinal metaplasia (n= 83), dysplasia (n= 25) and gastric carcinoma (n = 10) were studied by immunohistochemical stianing of proliferating cell nuclear antigen (PCNA).RESULTS: The gastric epithelial proliferation, expressed as PCNA labeling index (LI)%, was progressively increased in successive stages from normal mucosa to gastric carcinoma regardless of H. pylori status. There was significant difference in PCNA LI% among all groups (P <0.01). The analysis pursuing the effect of H. pylori infection on gastric epithelial proliferation in the progression from normal mucosa to gastriccarcinoma showed that in superficial gastritis and mild atrophic gastritis groups, PCNA LI% in H. pylori positive patients were 13.14 ± 1.6 and 19.68 ± 2.22 respectively, significantly higher than 6.95 ± 0.78 and 11.34 ± 1.89 in H. pylori negative patients (P <0.01); but there was no such difference in other groups (P >0.05).CONCLUSION:H. pylori infection causes increased gastric epithelial proliferation in the stages of superficial and mild atrophic gastritis and may play a part in triggering gastric carcinogenesis.
    World Journal of Gastroenterology 06/1998; 4(3):246-248. · 2.55 Impact Factor
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    ABSTRACT: In order to study the status of DNA methylation of specific oncogenes and the relationship between them and the pathological changes in gastric carcinoma, we analysed the methylated status of c-myc, c-Ha-ras oncogenes by Southern blot hybridization. Genomic DNA from cancerous, paracancerous and non-cancerous areas of surgically resected specimens were examined in 22 cases of advanced human gastric carcinoma. Specimens were digested by the restriction endonucleases MspI/HpaII, which are able to cleave between methylated and non-methylated cytosine at their nucleotide recognition site the DNA 5′-CCGG sequence, and were hybridized with c-myc, c-Ha-ras oncogene probes. Moreover, the corresponding pathological changes in gastric carcinoma were observed. The results showed that c-myc, c-Ha-ras oncogenes from cancerous (10/22, 5/10) and paracancerous areas (13/22, 4/10) were hypomethylated and that there was no significant relationship between them and the histopathological changes.
    Journal of Gastroenterology and Hepatology 10/1996; 11(11):1079 - 1082. · 3.33 Impact Factor

Publication Stats

103 Citations
16.83 Total Impact Points

Institutions

  • 2004–2007
    • Renji Hospital
      Shanghai, Shanghai Shi, China
  • 2006
    • Xuzhou Medical College
      Wu-hsien, Jiangsu Sheng, China
  • 1996–2002
    • Second Military Medical University, Shanghai
      Shanghai, Shanghai Shi, China